THE VALUE OF THE NITRATE FIGURE, ETC 



413 



wells in Table II (wells well away from cesspits) the marked 

 way in which the cesspit contamination has affected the 

 nitrogen as nitrate figure will be seen. 



Table II. — Showing Chemical Characters of Two other Well 

 Waters for comparison with Waters from the Eight Condemned 

 Wells. 





(9) 



(10) 





Analysed 



Analysed 





3.12.08. 29.10.08. 



3.12.0*. 



1. Total solid residue 



10-40 



13-24 



14-64 



2. Chlorine 



0-90 



0-95 



0-90 



3. Organic ammonia ... 



o-ooi 



0-004 



o-ooi 



4. Free ammonia 



0-002 



0-006 



0-002 



5. Nitrites 



o-ooo 



o-ooo 



o-ooi 



6. Nitrates 



0-200 



0-272 



0-050 



7. Oxygen absorbed 15 minutes 



0-008 



0-012 



0-008 



8. Oxygen absorbed 4 hours ... 



0-012 



0-020 



0-012 



9. Permanent hardness 



4-8 





1-5 



10. Total hardness 



6-0 



._.; 



10-5 



11, Poisonous metallic contamination 



none 



none 



none 



12. Alkalinity 



1-2 





9-0 



Figures equal to parts per 100,000. 



The following epidemiological evidence also pointed to 

 these wells being contaminated : — Population of the town 

 508, living in 125 houses. During the twelve weeks 17th 

 December 1908 to 7th March 1909 twenty-one cases of 

 typhoid fever occurred at this town, equal to an attack 

 rate of 41 per 1,000 of the population for less than a quarter 

 of the year. During the twelve months, March 1908 to 

 February 1909, thirty-seven cases of typhoid fever occurred, 

 equal to an attack rate of 72*8 per 1,000 of the population. 

 The attack rate for the whole of New South Wales for the 

 same twelve months was about 1*19 per 1,000 of the popu- 

 lation. Moreover, twelve cases occurred in one month, 

 February 1909, constituting almost an "explosion" in such 

 a small population. It will thus be seen to what an exces- 

 sive degree this town suffered from typhoid fever. 



The possible effect that the contaminated water had on 

 the typhoid incidence is shown by the next mentioned facts: 



